This invention relates to a method for producing a flexible composite hose, and to a hose produced by the method.
A prior art method of making a flexible composite hose includes extruding a thermosetting elastomeric material on a mandrel, applying a reinforcement material on the outer peripheral surface of the uncured elastomeric material, and extruding a thermosetting elastomeric material over the reinforcement material. Prior to vulcanization, the thermosetting elastomeric material is susceptible to physical damage due to the inability of the uncured material to resist plastic deformation. To avoid such physical damage, a lead jacket is extruded over the composite hose structure prior to vulcanization. The lead jacket acts as a mold during vulcanization to resist expansion and flow of the thermosetting elastomeric material at elevated temperatures. This method results in a highly compact product having a smooth outer periphery. Additionally, because the lead is somewhat rigid and less susceptible to plastic deformation than the uncured thermosetting elastomeric material, the lead jacket protects the hose from flatspotting during the vulcanization cycle. After curing, the lead jacket is stripped from the composite hose structure.
This process for making a composite hose structure is illustrated, for example, in U.S. Pat. No. 3,168,910. Other composite hose structures and methods using thermosetting elastomeric materials are shown in U.S. Pat. Nos. 3,921,674 and 3,953,270. A composite hose structure which does not require vulcanization is shown in U.S. Pat. No. 3,994,761. A particular thermoplastic elastomer is described in the publication titled "Thermoplastic Elastomers", available from Monsanto Industrial Chemicals Co., 260 Springside Drive, Akron, Ohio 44313.